A wafer cut out from a silicon single crystal obtained by a Czochralski method (which will be referred to as a CZ method hereinafter) has been conventionally used in order to manufacture a semiconductor device. In a device manufacturing process, a wafer undergoes various heat treatments and a slip may be produced in the wafer in some cases, but a regular batch type heat treatment furnace is used in a conventional process and a diameter of a wafer which is as small as 200 mm is primarily used, and hence occurrence of the slip is not a very serious problem.
However, in a state-of-the-art device manufacturing process in recent years, a single-wafer processing type heat treatment method such as SLA (Spike Lamp Anneal) or FLA (Flash Lamp Anneal) is used as a heat treatment which activates an ion-implanted impurity, and a distribution of the impurity in a depth direction is controlled in a narrow range, and hence there is carried out a heat treatment method which increases a temperature to a predetermined value at a very high speed and performs rapid cooling from this temperature. Therefore, a heat stress acting on the wafer becomes larger than that in the conventional process. On the other hand, a primary diameter of a wafer is shifting to a larger diameter like 300 mm, and a stress caused by a tare weight or a heat stress in a heat treatment also becomes larger when a wafer diameter is increased. Therefore, in the state-of-the-art process using a wafer having a diameter of 300 mm, a slip is apt to occur easily than ever, and deformation of the wafer also becomes considerable, leading to a reduction in a yield ratio of a device.
On the other hand, it is disclosed a semiconductor substrate which contains oxygen in the range of 5×1017 to 10×1017 atoms/cm3 and contains polyhedral (eight-faceted to 14-faceted) oxygen precipitates with a density in the range of 108 to 1010 pieces/cm3 in the region of 10 mm or below from a substrate outer periphery (see, e.g., Patent Document 1). In this semiconductor substrate, since the polyhedral oxygen precipitates contained with a density of 108 to 1010 pieces/cm3 inhibit movement of a dislocation which serves as a slip, occurrence of the slip from the outer peripheral portion of the substrate can be constrained at the time of a heat treatment in LSI manufacture.
Patent Document 1: Japanese Patent Application Laid-open No. 190954-1997 (claim 1, paragraph [0015])